Hi SD,
Yes, the modifications to the cable guides were unwise, but evidently suited the original owner's needs to swap the Rohloff-hubbed wheel and control cables to another bike for use there. It would have been far better to have invested in a second shifter and cable set for the other bike and simply swapped rear wheels.
Remember, the current seller did not do the modifications.
Yes, replacing cable guides is a fairly quick and easy job for a framebuilder, but it will damage the paint/powdercoat, so primer or a respray would have to be figured into the cost.
Best,
Dan.